This invention relates to an arrangement for combining a capacitance system within a sealed refrigeration system, and more particularly to a polypropylene film capacitor in a refrigeration system containing halocarbon fluid.
Capacitors used with single phase electric motors have been impregnated with oil to suppress corona by the oil filling the gaps or spaces left during the rolling of the capacitor. Capacitors employing metallized films of polyethylene terephthalate (Mylar) have been subjected to such gases as (CF.sub.2).sub.4 , C.sub.2 F.sub.5 C1 and Sf.sub. 6 for a period of time and voltage to increase the corona discharge voltage, as taught by Samoden in U.S. Pat. No. 3,206,826.
It has also been known that electrical apparatus can be insulated within an enclosed system by the use of insulating gases such as mixtures of SF.sub.6 and nitrogen and CC1.sub.2 F.sub.2. The use of these gases in a closed system is shown in U.S. Pat. No. 3,281,521. Also, perfluorobutane (C.sub.2 F.sub.6) has been suggested in place of the SF.sub.6.
Refrigerant systems are generally constructed of a condenser, a valve or capillary, an evaporator, a compressor, and conduits suitably connecting these parts. The compressor is driven by an electric motor. It is important that the refrigerant contained in the system and processed through the condenser and the evaporator by the action of the compressor not escape from the system. Accordingly, the parts of the system are interconnected so as to be as gas-tight as possible. This is done primarily by adequate sealing, but a factor in efficient retention of the fluid refrigerant is the arrangement of the parts. It is desirable to arrange the system so as to assist the sealing.
A compression refrigeration system has a motor-driven pump which circulates a halocarbon refrigerant fluid. In this system the compressor draws the halocarbon fluid in the gaseous phase of an evaporated vapor, compresses the vapor and passes the vapor to a condenser where the condensed vapor loses heat and turns into a liquid. The liquid is expelled from the condenser under high pressure to the expansion valve or capillary, where it evaporates back to the vapor phase, absorbing heat, in preparation for a return to the pump.
The compressor is driven by an electric motor which is contained within the enclosed system so that the drive to the compressor is completely within the system. Electric refrigerating system motors are completely sealed units permanently contained within the closed refrigerating system. The only breach in the system enclosure required is the provision for the power feed to the motor, the drive from the motor to the compressor being contained entirely within the system enclosure.
Capacitors are used in the electrical power circuit of refrigerating systems for the electric motor which drives the compressor. The motor-run capacitor is operated during the operating time of the motor and is thus under continuing demands. The effectiveness of the capacitor is related to its ability to meet the demands. Convolutely wound tubular capacitors are constructed by rolling spacer material between metal electrodes which are impregnated with a suitable impregnant of high dielectric constant.